In one known design of machine of the above kind, the elastically deformable element is an annular gasket ring with an L-shaped cross section, which is fitted on the outer radial edge of one of the axial ends of the stator. Axial clamping of the stator is obtained by means of a series of attached lugs, of which there may for example be three or four. These lugs are secured by means of screws into the part of the casing in which the stator, with its axially compressible gasket ring, has previously been centred.
That solution is not very satisfactory, because it makes it necessary to ensure beforehand that the stator is mounted and clamped axially in a first casing part using a first set of threaded fasteners, and then to assemble the two parts of the casing together by means of a further set of threaded fasteners.
In European patent specification EP 0 240 644A1, it was proposed to arrange an L-shaped compressible annular ring at each of the two axial ends of the stator, with each of these rings being received in one of the two parts of the casing. Again, this solution is rather unsatisfactory, because it requires concentric machining operations to be carried out in each of the two casing parts, in such a way that the stator will be correctly centred in its final position in the two rings with respect to the two casing parts, which also constitute the bearings for the rotor of the machine.
In addition, the fitting operations which comprise the fitting of a first ring in one of the casing parts, fitting of the stator in engagement against the first ring and then the second ring, and finally the closing of the assembly with the second casing part, are very complex and difficult to carry out blind.
The above mentioned patent specification EP 0 240 644A1 also discloses a modified embodiment in which the two L-shaped annular rings are joined together by means of longitudinal cylindrical pads or cushions. The difficulties met with in assembly of this arrangement are the same as those described above: in this connection, the longitudinal cylindrical pads are detrimental to correct angular positioning and to good axial clamping, because they prevent proper distribution of the forces involved since the cylindrical pads constitute a set of spacers between the annular rings.